restores and tests the write-through behavior on entrySet's toArray

The previous commit delegated an unbounded cache's toArray to the
underlying map. This works for keys and values, but an entry may be
modified. This wrote through to the map but bypassed being intercepted
for the removal listener. Additional unit tests now assert this to
avoid regressions, as the optimization seemed oddly missing and that
nagging feeling was a reminder of why.

caffeine/src/main/java/com/github/benmanes/caffeine/cache/UnboundedLocalCache.java

@@ -959,16 +959,6 @@ public Iterator<Entry<K, V>> iterator() {
     public Spliterator<Entry<K, V>> spliterator() {
       return new EntrySpliterator<>(cache);
     }
-
-    @Override
-    public Object[] toArray() {
-      return cache.data.entrySet().toArray();
-    }
-
-    @Override
-    public <T> T[] toArray(T[] array) {
-      return cache.data.entrySet().toArray(array);
-    }
   }
 
   /** An adapter to safely externalize the entry iterator. */

caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsMapTest.java

@@ -47,6 +47,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.Set;
 import java.util.Spliterators;
 import java.util.concurrent.CompletableFuture;
@@ -2584,6 +2585,42 @@ public void entrySet_toArray(Map<Int, Int> map, CacheContext context) {
 
     var func = map.entrySet().toArray(Map.Entry<?, ?>[]::new);
     assertThat(func).asList().containsExactlyElementsIn(context.original().entrySet());
+
+    if (context.isCaffeine()) {
+      for (var entry : array) {
+        assertThat(entry).isInstanceOf(WriteThroughEntry.class);
+      }
+      for (var entry : ints) {
+        assertThat(entry).isInstanceOf(WriteThroughEntry.class);
+      }
+      for (var entry : func) {
+        assertThat(entry).isInstanceOf(WriteThroughEntry.class);
+      }
+    }
+  }
+
+  @CheckNoStats
+  @Test(dataProvider = "caches")
+  @CacheSpec(population = Population.FULL,
+      removalListener = { Listener.DISABLED, Listener.CONSUMING })
+  public void entrySet_toArray_writeThrough(Map<Int, Int> map, CacheContext context) {
+    var expected = new HashMap<>(context.original());
+    expected.putAll(Maps.toMap(context.firstMiddleLastKeys(), key -> context.absentValue()));
+
+    @SuppressWarnings("unchecked")
+    var array = (Map.Entry<Int, Int>[]) map.entrySet().toArray(new Map.Entry<?, ?>[0]);
+    for (var entry : array) {
+      var value = expected.get(entry.getKey());
+      if (!Objects.equals(entry.getValue(), value)) {
+        entry.setValue(value);
+        assertThat(entry.getValue()).isEqualTo(value);
+      }
+    }
+    assertThat(map).isEqualTo(expected);
+    assertThat(context).removalNotifications().withCause(REPLACED)
+        .contains(Maps.toMap(context.firstMiddleLastKeys(),
+            key -> requireNonNull(context.original().get(key))))
+        .exclusively();
   }
 
   @CheckNoStats
@@ -2939,6 +2976,9 @@ public void entrySet(Map<Int, Int> map, CacheContext context) {
       assertThat(entries.remove(entry)).isTrue();
       assertThat(entries.remove(entry)).isFalse();
       assertThat(entries).doesNotContain(entry);
+      if (context.isCaffeine()) {
+        assertThat(entry).isInstanceOf(WriteThroughEntry.class);
+      }
     });
     assertThat(map).isExhaustivelyEmpty();
     assertThat(context).removalNotifications().withCause(EXPLICIT)

caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncCacheTest.java

@@ -361,7 +361,7 @@ public void getBiFunc_absent_cancelled(AsyncCache<Int, Int> cache, CacheContext
   @Test(dataProvider = "caches")
   public void getBiFunc_absent(AsyncCache<Int, Int> cache, CacheContext context) {
     Int key = context.absentKey();
-    var value = cache.get(key, (k, executor) -> context.absentValue().asFuture());
+    var value = cache.get(key, (k, executor) -> context.absentValue().toFuture());
     assertThat(value).succeedsWith(context.absentValue());
     assertThat(context).stats().hits(0).misses(1).success(1).failures(0);
   }
@@ -1071,7 +1071,7 @@ public void getAllBifunction_early_failure(AsyncCache<Int, Int> cache, CacheCont
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void put_nullKey(AsyncCache<Int, Int> cache, CacheContext context) {
-    var value = context.absentValue().asFuture();
+    var value = context.absentValue().toFuture();
     assertThrows(NullPointerException.class, () -> cache.put(null, value));
   }
 
@@ -1121,7 +1121,7 @@ public void put_insert_failure_after(AsyncCache<Int, Int> cache, CacheContext co
   @Test(dataProvider = "caches")
   @CacheSpec(removalListener = { Listener.DISABLED, Listener.REJECTING })
   public void put_insert(AsyncCache<Int, Int> cache, CacheContext context) {
-    var value = context.absentValue().asFuture();
+    var value = context.absentValue().toFuture();
     cache.put(context.absentKey(), value);
     assertThat(cache).hasSize(context.initialSize() + 1);
     assertThat(context).stats().hits(0).misses(0).success(1).failures(0);
@@ -1173,7 +1173,7 @@ public void put_replace_nullValue(AsyncCache<Int, Int> cache, CacheContext conte
   public void put_replace_differentValue(AsyncCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, Int>();
     for (Int key : context.firstMiddleLastKeys()) {
-      var newValue = context.absentValue().asFuture();
+      var newValue = context.absentValue().toFuture();
       cache.put(key, newValue);
       assertThat(cache).containsEntry(key, newValue);
       replaced.put(key, context.original().get(key));

caffeine/src/test/java/com/github/benmanes/caffeine/cache/AsyncLoadingCacheTest.java

@@ -503,7 +503,7 @@ private static final class LoadAllException extends RuntimeException {
   @CacheSpec(population = { Population.SINGLETON, Population.PARTIAL, Population.FULL })
   public void put_replace(AsyncLoadingCache<Int, Int> cache, CacheContext context) {
     var replaced = new HashMap<Int, Int>();
-    var value = context.absentValue().asFuture();
+    var value = context.absentValue().toFuture();
     for (Int key : context.firstMiddleLastKeys()) {
       cache.put(key, value);
       assertThat(cache.get(key)).succeedsWith(context.absentValue());
@@ -629,7 +629,7 @@ public void refresh_current_inFlight(AsyncLoadingCache<Int, Int> cache, CacheCon
   @Test(dataProvider = "caches")
   @CacheSpec(compute = Compute.ASYNC, removalListener = Listener.CONSUMING)
   public void refresh_current_sameInstance(CacheContext context) {
-    var future = context.absentValue().asFuture();
+    var future = context.absentValue().toFuture();
     var cache = context.buildAsync((key, executor) -> future);
 
     cache.put(context.absentKey(), future);
@@ -640,7 +640,7 @@ public void refresh_current_sameInstance(CacheContext context) {
   @CacheSpec
   @Test(dataProvider = "caches")
   public void refresh_current_failed(AsyncLoadingCache<Int, Int> cache, CacheContext context) {
-    var future = context.absentValue().asFuture();
+    var future = context.absentValue().toFuture();
     cache.put(context.absentKey(), future);
 
     future.obtrudeException(new Exception());
@@ -662,7 +662,7 @@ public void refresh_current_removed(CacheContext context) {
       return key;
     });
 
-    cache.put(context.absentKey(), context.absentValue().asFuture());
+    cache.put(context.absentKey(), context.absentValue().toFuture());
     cache.synchronous().refresh(context.absentKey());
     await().untilTrue(started);
 
@@ -679,14 +679,14 @@ public void refresh_current_removed(CacheContext context) {
 
   @Test
   public void asyncLoadAll() {
-    AsyncCacheLoader<Int, Int> loader = (key, executor) -> key.negate().asFuture();
+    AsyncCacheLoader<Int, Int> loader = (key, executor) -> key.negate().toFuture();
     assertThrows(UnsupportedOperationException.class, () ->
         loader.asyncLoadAll(Set.of(), Runnable::run));
   }
 
   @Test
   public void asyncReload() throws Exception {
-    AsyncCacheLoader<Int, Int> loader = (key, executor) -> key.negate().asFuture();
+    AsyncCacheLoader<Int, Int> loader = (key, executor) -> key.negate().toFuture();
     var future = loader.asyncReload(Int.valueOf(1), Int.valueOf(2), Runnable::run);
     assertThat(future).succeedsWith(-1);
   }

caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpirationTest.java

@@ -484,7 +484,7 @@ public void get(AsyncCache<Int, Int> cache, CacheContext context) {
 
     cache.get(context.firstKey(), k -> k).join();
     cache.get(context.middleKey(), k -> context.absentValue()).join();
-    cache.get(context.lastKey(), (k, executor) -> context.absentValue().asFuture()).join();
+    cache.get(context.lastKey(), (k, executor) -> context.absentValue().toFuture()).join();
 
     assertThat(context).notifications().withCause(EXPIRED)
         .contains(context.original()).exclusively();
@@ -573,7 +573,7 @@ public void getAll(AsyncCache<Int, Int> cache, CacheContext context) {
       expireAfterWrite = {Expire.DISABLED, Expire.ONE_MINUTE})
   public void put_insert(AsyncCache<Int, Int> cache, CacheContext context) {
     context.ticker().advance(Duration.ofMinutes(1));
-    cache.put(context.firstKey(), intern(context.absentValue().asFuture()));
+    cache.put(context.firstKey(), intern(context.absentValue().toFuture()));
 
     runVariableExpiration(context);
     assertThat(cache).hasSize(1);
@@ -613,7 +613,7 @@ public void put_insert_async(AsyncCache<Int, Int> cache, CacheContext context) {
       expireAfterAccess = {Expire.DISABLED, Expire.ONE_MINUTE},
       expireAfterWrite = {Expire.DISABLED, Expire.ONE_MINUTE})
   public void put_replace(AsyncCache<Int, Int> cache, CacheContext context) {
-    var future = context.absentValue().asFuture();
+    var future = context.absentValue().toFuture();
     context.ticker().advance(Duration.ofSeconds(30));
 
     cache.put(context.firstKey(), future);

caffeine/src/test/java/com/github/benmanes/caffeine/cache/ExpireAfterVarTest.java

@@ -200,7 +200,7 @@ public void put_replace(Cache<Int, Int> cache, CacheContext context) {
   @CacheSpec(population = Population.FULL,
       expiryTime = Expire.ONE_MINUTE, expiry = CacheExpiry.CREATE)
   public void put_replace(AsyncCache<Int, Int> cache, CacheContext context) {
-    var future = context.absentValue().asFuture();
+    var future = context.absentValue().toFuture();
     context.ticker().advance(Duration.ofSeconds(30));
 
     cache.put(context.firstKey(), future);

caffeine/src/test/java/com/github/benmanes/caffeine/cache/ReferenceTest.java

@@ -523,7 +523,7 @@ public void put_async(AsyncCache<Int, Int> cache, CacheContext context) {
     Int key = context.absentKey();
     context.clear();
     GcFinalization.awaitFullGc();
-    cache.put(key, context.absentValue().asFuture());
+    cache.put(key, context.absentValue().toFuture());
 
     assertThat(cache).hasSize(1);
     assertThat(context).notifications().withCause(COLLECTED)

caffeine/src/test/java/com/github/benmanes/caffeine/cache/RefreshAfterWriteTest.java

@@ -104,7 +104,7 @@ public void refreshIfNeeded_nonblocking(CacheContext context) {
       public CompletableFuture<Int> asyncReload(Int key, Int oldValue, Executor executor) {
         reloads.incrementAndGet();
         await().untilTrue(refresh);
-        return oldValue.add(1).asFuture();
+        return oldValue.add(1).toFuture();
       }
     });
     cache.put(key, original);

caffeine/src/test/java/com/github/benmanes/caffeine/testing/Int.java

@@ -83,8 +83,8 @@ public Int add(Int i) {
     return add(i.value);
   }
 
-  /** Returns a completed future of this value. */
-  public CompletableFuture<Int> asFuture() {
+  /** Returns a new completed future for this value. */
+  public CompletableFuture<Int> toFuture() {
     return CompletableFuture.completedFuture(this);
   }
 
@@ -155,9 +155,9 @@ public static Map<Int, Int> mapOf(int... mappings) {
     return map;
   }
 
-  /** Returns a completed future of the value, possibly cached. */
+  /** Returns a new completed future of the (possibly cached) value. */
   public static CompletableFuture<Int> futureOf(int i) {
-    return valueOf(i).asFuture();
+    return valueOf(i).toFuture();
   }
 
   /** Returns a preallocated range of {@code Int} instances */